Andrew Marr was “being polite” to Conservative minister Penny Mordaunt because he is an “actual human”, the editor of the BBC’s flagship politics programme has said after an unguarded on-air thumbs-up prompted a rash of online conspiracy theories.

Mordaunt, the International Development Secretary, was appearing on the Sunday morning programme to discuss the sexual misconduct allegations against Oxfam workers.

As the interview turned to Brexit at its conclusion, the Cabinet minister insisted she was still “chipper” about the process.

As he handed over to Nick Campbell for a preview of the next show, Marr appeared to give Mordaunt a thumbs-up and tell her “that was very good”.